1. Field of the Invention.
The invention relates to the field of magnetic bubble detection.
2. Prior Art.
In the fabrication of magnetic bubble (single wall domain) devices, particularly magnetic bubble memories, it is important to limit the number of connections that must be made between the memory substrate and external circuits. Also, it is advantageous to use as few as possible external circuits and to have, for example, the same driving circuit power two bubble generators. In copending application Ser. No. 25,848, filed Apr. 2, 1978 amd now U.S. Pat. No. 4,272,817 entitled "Multiplexed Single Wall Domain Generators", (assigned to the assignee of the present application), a system is described for multiplexing bubble generators. As will be seen, the present invention teaches an apparatus for multiplexing the outputs of bubble detectors.
There have been attempts in the past to multiplex bubble detector outputs. In one scheme, four chevron detectors are formed at different angular orientations. For example, the detectors are oriented each 90 degrees from the other, like spokes of a wheel. Then, the detectors are coupled to a common sensing circuit. One problem with this scheme is described in conjunction with FIG. 3a of the specification.
Another aspect of the present invention is a method for optimizing the signal level output from each of the multiplexed bubble detectors. One process for adjusting the signal level from a magnetic bubble detector is described in copending application Ser. No. 163,574 filed June 27, 1980, now U.S. Pat. No. 4,300,209 entitled "Method for Adjusting Signal Level Output from Magnetic Bubble Detector", assigned to the assignee of the present application.